NY-BR-1 is a novel differentiation marker predominantly expressed in normal breast and breast cancer. It has been shown by Immunohistochemistry (IHC) that NY-BR-1 was present solely in ductal epithelium of normal breast tissue. Invasive carcinoma of the breast and carcinoma in situ were positive for NY-BR-1, whereas most other tumors and normal tissues are negative, with the exceptions of one-third of sweat gland carcinomas and around two percent of prostate carcinoma. NY-BR-1 is reported to express more frequently in estrogen-positive and lymph node-negative primary carcinomas, and more commonly in grade 1 than in grade 2 or grade 3. In a study by Varga et al (2006) forty-nine percent of lymph node metastasis were shown to be positive.